1. Field of the Invention
The present invention relates generally to a message service method for a mobile communication terminal, and more particularly to a method and system for providing a destination user with a messaging service or a security messaging service when conditions reserved by an origination user are met.
2. Description of the Related Art
Conventionally, a mobile communication terminal (also called a mobile station) has provided a text message service or an SMS (Short Message Service) widely used for a special control function of the mobile communication terminal. Recently, however, a variety of message services, for example, a multimedia message service, an E-mail service, an instant messenger service, etc., are currently being provided to users, and other improved message services will be provided to the users in the future.
Accordingly, he aforementioned message service includes a basic service for providing users with only messages and an additional service for enabling a transmission user to establish a specific condition required for transmitting desired messages to a reception user. For example, the additional service may be an origination time reservation time for the SMS service. More Specifically, when the transmission user reserves a message origination time of a predetermined text message, a mobile terminal or a mobile communication network transmits a corresponding text message to a receiver mobile terminal at the reserved time such that a reception user can recognize the text message.
As another example, the additional service may be a text message broadcasting service for simultaneously broadcasting a text message to mobile terminals positioned in a specific area at one time. This function has been widely used for commercial purposes. For example, a specific company may distribute discount coupons to a plurality of mobile terminals positioned within a predetermined range of a business place.
The message service for the mobile terminal is required for transmitting a desired message to a reception user, and provides additional functions for reserving an origination time or determining a specific area, resulting in greater convenience for the user.
The origination time reservation function can reserve only a message origination time. The function for transmitting a message to a plurality of mobile terminals positioned in a specific area is unable to determine individual mobile terminals that will receive the message, and the mobile terminals not positioned in the specific area at the message transmission time are unable to receive the message.
However, when a specific mobile terminal determined by the transmission user is positioned within a desired range of the transmission user, the transmission user may wish to transmit a message to the specific mobile terminal user. For example, when staff of a specific company attends their offices, official announcement messages for all offices or all sections may be required to be displayed on mobile terminals of corresponding staff. For another example, if a user must travel on a business trip, the user may wish to receive a message indicating of principal programs that must be performed at the business place, upon arrival at the business place.
When receiving the message, the mobile terminal for providing users with message service functions displays a specific message indicating that the message has been received, in order for the user to recognize the message reception. Provided that a user establishes a function for displaying reception message contents, the reception message contents are also displayed on a display. Accordingly, if the reception message contents are automatically displayed at a message reception time, not only a mobile terminal user but also other users can see the message. Further, if a user leaves the mobile terminal somewhere in the view of others and then leaves the place even though a function for displaying the reception message contents is released, other users may operate the user's mobile terminal to view the message contents.
Commonly, a mobile terminal has a locking function to prevent others who do not know a password set by a user from fraudulently operating the user's mobile terminal. If the user establishes the locking function, although the user leaves his or her mobile terminal somewhere in view of other users and then leaves the place, the other users are unable to operate the user's mobile terminal and cannot view the message contents. However, the locking function is adapted to lock the mobile terminal, instead of locking just a message reading function. Accordingly, if the aforementioned locking function is established, the user must enter his or her password whenever the user uses the mobile terminal, and must re-establish the locking function after using the mobile terminal, resulting in greater inconvenience for the user. As a result, most users rarely use the aforementioned locking function.
Therefore, a mobile terminal requires a message security service to prevent message contents from being exposed to others. There are many technologies for implementing the message security service. For example, one method encrypts a desired message using an encryption key negotiated between a transmission user and a reception user. The transmission mobile terminal receives the encryption key from the transmission user, encrypts the message using the encryption key, and transmits the encrypted message. The reception mobile terminal receives a decryption key matching the encryption key from the reception user, decrypts the received encryption message using the received decryption key, and displays the decrypted result message. Therefore, only the reception user determined by the transmission user can view the message contents, resulting in message security implementation.
However, the aforementioned technology for implementing message security using an encryption key negotiated between the transmission user and the reception user must enable the transmission user to share the encryption key with the reception user. Therefore, the encryption key is in danger of being hacked when the transmission user and the reception user share the encryption key. Further, if the reception user forgets the encryption key, the reception user is unable to recognize the encryption message contents.
Provided that the user finds the encryption key and the message is initially opened, the message can viewed anywhere, such that it is difficult to guarantee message security when the mobile terminal is stolen or lost.
That is, although the message is encrypted, this message is preserved until the reception user deletes the message even when the transmission user does not want to preserve the message, such that the possibility of fraudulently exposing the message contents to others increases.